How to convert materials into textures in EEVEE?
As of July of this year, you can't bake Eevee-specific elements to textures, since Eevee itself doesn't support baking.

There's a discussion about this on the blender community page

https://blender.community/c/rightclickselect/X0dbbc/

The main takeaway from the original post there is;

"Baking isn't currently available in Eevee in any form." -jpgarsemailbox

If you have an object that uses non-Eevee-specific nodes, you could bake it in Cycles (et al) and bring it back into Eevee. You might even be able to bake everything except the Eevee-specific parts, then layer those on top after backing in another renderer.